A switched-mode power converter (also referred to as a “power converter”) is a power supply or power processing circuit that converts an input voltage waveform into a specified output voltage waveform. DC-DC power converters convert a direct current (“DC”) input voltage into a DC output voltage. Controllers associated with the power converters manage an operation thereof by controlling conduction periods of power switches employed therein. Generally, the controllers are coupled between an input and output of the power converter in a feedback loop configuration (also referred to as a “control loop” or “closed control loop”).
Typically, the controller measures an output characteristic (e.g., an output voltage, an output current, or a combination of an output voltage and an output current) of the power converter, and based thereon modifies a duty cycle of a power switch of the power converter. The duty cycle “D” is a ratio represented by a conduction period of a power switch to a switching period thereof. In other words, the switching period includes the conduction period of the power switch (represented by the duty cycle “D”) and a non-conduction period of the power switch (represented by the complementary duty cycle (“1-D”). Thus, if a power switch conducts for half of the switching period, the duty cycle for the power switch would be 0.5 (or 50 percent).
The switched-mode power converters can be constructed with different types of power switches such as bipolar transistors, metal-oxide semiconductor field-effect transistors (“MOSFETs”) or insulated gate bipolar transistors (“IGBTs”). At low power levels, for example, an output power less than 100 watts (“W”), the MOSFETs and bipolar transistors are most commonly used for power switches. While MOSFETs can work at higher switching frequency, which enables smaller designs, bipolar transistors are available at lower cost. Additionally, the different switches employ different drivers for their respective control terminals. As a result, separate driver integrated circuits are inventoried to accommodate the use of different switches in a design of a circuit (e.g., a power converter) employing the same.
Accordingly, what is needed in the art is a circuit and related method for a switch that enables a driver to be used for different types of switches such as MOSFETs and bipolar transistors that can be adapted to high-volume manufacturing techniques for a power converter or the like employing the same.